Bala,

Niels has suggested us to add explanation on why it is important to create 8 block devices and configure them as RAID-0. Could you help us by providing an explanation for the same?

Thanks,
Divya

My reply,

Our benchmark on AWS environment shows that any single EBS volume doesn't give consistent I/O performance and its quite variable.  When using 8 EBS volumes on RAID-0 shows consistent I/O performance.  This is achieved by striping over 8 EBS volumes.  As I/O performance of each block device is important which directly affects glusterfs performance, having 8 EBS volumes on RAID-0 is required.

Hi Niels, Bala,

I am planning to update the Important section as follows:

---
Important

Single EBS volume shows inconsistent I/O performance. Red Hat supported configuration is 8 Amazon EBS volumes of equal size on software RAID 0 (stripe) attached to a brick. You can create a brick ranging from 8 GB to 8 TB. If your environment uses 8 EBS volumes on software RAID 0 (stripe), the I/O performance is consistent. For example, if you create a brick of 128 GB, you must create 8 Amazon EBS volumes of size 16 GB each and then create RAID 0 (stripe).

---

Please let me know your comments.

Regards,
Divya

I would like

'''
Important

Single EBS volume shows inconsistent I/O performance. To overcome this, Red Hat supported configuration is 8 Amazon EBS volumes of equal size on software RAID 0 (stripe) attached to a brick to make consistent I/O performance. You can create a brick ranging from 8 GB to 8 TB. If your environment uses 8 EBS volumes on software RAID 0 (stripe), the I/O performance is consistent. For example, if you create a brick of 128 GB, you must create 8 Amazon EBS volumes of size 16 GB each and then create RAID 0 (stripe).
'''

+1 to comment #4 from Bala.

Added explanation on why 8 EBS volumes is important and link to the updated guide: http://documentation-devel.engineering.redhat.com/docs/en-US/Red_Hat_Storage/2.0/html/Administration_Guide/chap-User_Guide-Provisioning_Storage.html